The dough needs to be made the day or night before you assemble and bake your gata. Start by adding the baking soda and baking powder to the sour cream and mix it until thoroughly combined. Set aside.

Add half the flour and half the butter to the bowl of a food processor (if you have a really large food processor bowl you can do it all at once, but it’s best to split it up if not). Pulse the mixture several times until it looks sandy and contains small pea-sized bits of butter.

Add half the sour cream mixture and mix until it comes together into a doughy mass. Remove the dough to a lightly floured cutting board or work surface and repeat with the remaining flour, butter, and sour cream mixture in the food processor. Add the other half of the dough to the dough already on the work surface and gently press it together to form a single dough (do not knead it, but just absorb one dough half into the other).

The following day, make the filling. Add the flour and butter to the bowl of a food processor and pulse the mixture several times until it looks sandy and contains small pea-sized bits of butter. Add the sugar and vanilla and quickly pulse just a few more times to combine, but not enough to form a dough. Pour this crumbly filling into a wide, flat bowl and use a large spoon to divide it into four quadrants (just draw lines). Set aside.

Remove two of the refrigerated dough squares from the refrigerator at a time. Lightly flour a work surface and gently roll out one of the dough squares into a rectangle about 1/16th-inch thick and about with dimensions of about 12-by-15-inches (this doesn’t have to be perfect, and may be slightly different in size if your four pieces of dough weren’t divided evenly). Do your best to create straight edges and corners for your rectangle, and an even thickness, dusting with minimal flour as necessary. Arrange the rectangle so the longest edge is facing you with the shorter edges on either side.

Beginning with the edge closest to you, start rolling the dough tightly. Sometimes it’s easier to simply make a small fold across the length, using your dough scraper for assistance, and then continue with the rolling. When finished rolling, gently press the top of the roll to help seal.

Carefully move your roll to a clean piece of parchment or wax paper on your work surface. Lay it diagonally if you must so it doesn’t hang off the edges. Use your rolling pin to gently flatten the roll starting at the center and moving outward, and then again starting at the center and moving outward in the opposite direction. You are not rolling it out, but just using the natural momentum of the rolling pin to flatten it so it’s not rounded like a jelly roll.

When finished with the first roll, dump out any extra crumbs from your parchment paper (as long as they’re not eggy) back into the bowl of filling, and use your dough scraper to clean any extra crumbs from you original work surface and add those back to the bowl as well.

Repeat the process with the remaining dough squares on your clean, lightly floured work surface (you can fold the parchment in half lengthwise and reuse it again once more, and then start fresh on dough #3 with a clean piece).

Bake the gata one tray at a time for about 25 to 35 minutes, rotating the pan from front to back about halfway through baking, until the tops are dark golden brown, and the dough on the sides is no longer pasty looking, and appears to be cooked through (it may even start to look slightly golden). Remove from the oven and replace with the next pan of gata. Repeat the baking process until all pans are baked, one at a time.

Cool the gata completely before removing from the baking sheets. To store, place them either on a large baking sheet, pan, or serving dish, but cover with a large tea towel as opposed to foil or plastic wrap, which will cause the gata to soften.